This invention relates to dies that are used in presses for reloading ammunition cartridges.
Dies for reloading ammunition cartridges (hereafter called casings) are customarily screwed into a turret of any of a variety of commercially available reloading presses. A sizing and decapping die is rotatable with the turret selectively into alignment with a lever-driven ram which drives the casing into the sizing and decapping die. After the casing is recapped and refilled with powder, the turret is rotated to align the bullet seater die with the ram and the bullet seating operation is performed.
Insofar as prior art sizing and decapping die assemblies are concerned, the weakest and most frequently failing part is the decapper and the rod to which it is attached. Ordinarily, this rod is threaded into the internal thread of a nut, adjusted and locked into place with a jamb nut. This assembly is then threaded into the sizing die in alignment with its axially extending casing receiving bore. If the rod is misadjusted when assembled or becomes misadjusted through use, it is quite vulnerable to being damaged. This occurs because, during the time that maximum pressure is applied to size the casing, the operator will not feel the slight additional resistance to ram movement that the misadjusted rod causes.
The lower end of the decapping rod is customarily provided with a decapping pin which drives the spent cap or primer out of the rim of the casing at about the time that the casing reaches its limiting position in the sizing die. In accordance with prior practice, the decapping pin is threaded into an end of the decapping rod or into an adapter that is threaded on the rod. This approach requires multiple machining steps, one being to cut an external thread on the small diameter decapping pin and another to tap a thread in the small hole in the end of the decapping rod that receives the pin. More often than not, a slight misalignment results between the axes of the threaded hole and decapping pin so the pin is often slightly out of alignment and angulated with respect to the axis of the rod. Threads also weaken the pin. The result has been frequent breakage of the pin. In fact, breakage of these prior art decapping assemblies is expected to be and is so frequent that the pins are considered expendable and means are provided by the manufacturer for replacing them. This means that the user is obliged to acquire more parts and yet not resolve the problem of thread misalignment.
Prior art bullet seating dies are also problematical. The bullet-seater is customarily a cylindrical body that has an external thread for screwing it into the turret. It is adjusted in or out on the thread so that the contoured surface inside of the seater bore that pushes on the nose of the bullet to seat it to the proper depth in the casing is centered on a threaded shank. The accuracy of this construction is dependent upon the accuracy of the machining of the threads. Because the threaded end of the bullet seating die is at the extreme opposite end of the die that the casing is inserted into, it necessitates two different threading machine operations. Machinists are aware that it is impossible to obtain perfect alignment between two threaded parts. With the tolerances found in commercial production machines, it is quite possible to have a misalignment of 1/64 inch or more.